Multiple speed cooling fan drive mechanism



Sept. 6, 1966 G. L. BOWEN ET AL 3,270,588

MULTIPLE SPEED COOLING FAN DRIVE MECHANISM Filed Nov. 4. 1963 5 Sheets-Sheet 1 INVENTORS: GLEN L.BOWEN BY ROBERT W. LEMON ATTORNEYS G. L. BOWEN ET AL 3,270,588

MULTIPLE SPEED COOLING FAN DRIVE MECHANISM 5 Sheets-Sheet 2 Sept. 6, 1966 Filed Nov. 4, 1963 70 HIGH RANGE L LOW A/G CLUTCH 7-0 CZU fiCfil E HYD. T \/\/1 T I Z wmzock Z66 T 266 W I i J I eeuucm low /vur. T O T 60L. T

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244 246 SUPPLY H/GH LOW wars/2 TEMP. mm 05750702 6W/TCH aw/m/ sw/rcw INVENTORS.

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ATTORNEYS Sept. 6, 1966 G. L. BOWEN ET AL. 3,270,588

MULTIPLE SPEED COOLING FAN DRIVE MECHANISM Filed Nov. 4, 1963 5 Sheets-Sheet :5

Qmmkm RE 89/14001980/1 IVbJ INVENTOR5. GLEN L- BOWEN BY ROBERT W.LEMON CD 7 ATTORNEYS United States Patent Office 3,27%,5fi3 Patented Sept. 6, 1966 3,270,588 MULTEPLE SPEED QOOLING FAN DRIVE MECHANISM Glen L. Bowen, Detroit, and Robert W. Lemon, Farmington, Mich, assignors to G. I... Bowen 8; (10., Oak Park,

Mich, a corporation of Michigan Filed Nov. 4, 1963, Ser. No. 321,183 14 Claims. (Cl. 7475tl) Our invention relates generally to engine cooling fan drives for liquid cooled internal combustion engines, and

more particularly to an engine cooling fan drive having two speed ratios that can be established and interrupted automatically in accordance with the cooling requirements of the engine.

In a d-riveline installation employing the improvements of our invention, the liquid cooled internal combustion engine is provided with a liqu-id-to air radiator core having flow passages through which the engine coolant is circulated by means of a coolant pump. A cooling air fan is disposed adjacent the radiator core to establish a passage gradient that will cause the ambient air to flow through the core and dissipate the heat of the coolant. Since the cooling air fan is powered by the engine, the horsepower requirements of the fan represent a net horsepower loss. This horsepower loss can be reduced to a minimum, however, if the speed ratio of the fan drive is controlled so that the power absorbed by the fan is not greatly in excess of that which is required to satisfy the cooling requirements of the engine.

We contemplate that our improved driveline can be used in an amphibious vehicle having an engine with a horsepower rating in excess of one thousand horsepower. In an installation of this type, it is uneconomical to use a constant speed ratio drive with a cooling fan that is designed to satisfy the maximum cooling requirements of the engine since the cooling capacity of the fan during operation of the engine at lower horsepower then, of necessity, would be excessive. By properly cont-rolling the speed ratio of the fan drive, it is possible to reduce the power loss by as much as ninety-five horsepower during cold weather operation and when the vehicle is waterborne.

The provision of an improved fan drive of the type above set forth being a principal object of our invention, it is another object of our invention to provide a fan drive and control system of the type above set forth wherein the fan will be disengaged automatically from its power source while the amphibious vehicle is water-borne thereby preventing fan damage by the water.

It is a further object of our invention to provide a control system for a multiple speed fan drive of the type above set forth wherein provision is made for interrupting the power delivery path that extends from the vehicle engine to the fan when the engine coolant temperature is below a predetermined value and wherein an automatic shift of the fan drive from the neutral condition to either a low speed range or a high speed range will be accomplished automatically as the cooling requirements of the engine increase.

It is a further object of our invention to provide a fan drive and control system of the type above set forth wherein provision is made for shifting the drive automatically into the high speed range upon a failure in the control system.

It is a further object of our invention to provide a torque delivery clutch mechanism of the multiple disc type in a d-riveline for a multiple speed fan of the type above set forth and which is characterized by its ability to assume either a horizontal position or a vertical position without undesirable drag of the friction elements of the clutch structure when the clutch is disengaged.

It is a further object of our invention to provide a control system for a multiple speed fan drive of the type above set forth wherein provision is made for changing automatically the driving speed ratio in response to changes in the temperature of the ambient air.

It is a further object of our invention to provide a multiple speed fan drive having a fluid pressure operated friction clutch that acts as 'a torque delivery component and assumes a torque delivery condition upon an interruption in the supply of clutch pressure.

It is a further object of our invention to provide a multiple speed fan drive of the type above set forth wherein provision is made for shifting the drive automatically into a high speed ratio range upon .a control system failure.

It is a further object of our invention to provide a multiple speed fan drive for an internal combustion engine that is characterized by its reduced axial and transverse dimensions.

Further objects and features of our invention will become apparent from the following description and the accompanying drawings wherein:

FIGURE 1 shows a longitudinal cross sectional view of the torque delivery components of our improved fan drive;

FIGURE 2 shows in schematic form a control system diagram for controlling the operation of the torque delivery clutches shown in FIGURE 1; and

FIGURE 3 shows a horsepower curve for our improved fan drive in a typical driveline installation.

Referring first to FIGURE 1, numeral 10 designates generally a main transmission housing having a relatively large diameter portion 12. that encloses a front direct drive clutch structure 14. It includes also a relatively reduced diameter portion 15 that encloses a rear underdrive clutch structure 16 and a simple planetary gear unit 18.

A power input shaft 20 extends axially through the housing 10 and is adapted to be connected at its outboard end 22 to the vehicle engine. An opening 24 can be provided at the end of the housing 10 to accommodate a bearing and a fluid seal, not shown.

The planetary gear unit 18 includes a ring gear 26, a sun gear 28 and planet pinions 30. Pinion shafts 32 rotata-bly support the pinions 30, suitable needle bearings 34 being provided for this purpose.

Shafts 32 are supported by carrier 36 which in turn is riveted or otherwise secured to a radial flange 38 formed on a sleeve shaft 40. The shaft 20 is received through the sleeve shaft 40.

Pinions 30 are disposed in driving relationship with respect to the sun gear 28 and the ring gear 26.

A drive plate 42 is splined at its outer periphery to the ring gear 18 and held axially fast with respect thereto by a snap ring 44. Plate 42 includes a hub 46 that is internally splined at 48 to the shaft 20.

Hub 46 extends through a bearing opening formed in end Wall 50 and is journalled therein by means of a bushing 52.

A positive displacement pump having pump gear elements 54 and 56 is enclosed within a pump chamber 58 formed in an adaptor 60. Gear element 54 is doweled or otherwise positively connected to the hub 46. Adaptor 60 is bolted by means of bolts 62 to the end wall 50. A spacer bushing 64 is disposed between adaptor 60 and the drive plate 42 for accommodating axial thrust.

A fluid pressure discharge port 66 is formed in the end wall 50 and communicates with a high pressure feed passage 68. A control pressure line can be connected to passage 68 by means of a threaded fitting, not shown.

3 The wall can be threaded at to accommodate the fitting.

An intermediate wall is shown at 72. It is connected by means of set screws 74 to a retainer ring 76, the latter being welded to the interior of the housing portion 16. Sun gear 28 is keyed at 78 to the wall 72 so that it is held stationary. A thrust washer 80 is disposed between sun gear 28 and the flange 38. Another thrust washer 82 is disposed between the flange 38 and the member 42.

Wall 72 has secured thereto a stationary sleeve shaft extension 84. Sleeve shaft 40 is received within the extension 84 and is journalled therein by means of the bushing 86. Another bushing 88 is disposed between sleeve shaft 40 and the sun gear 28.

A clutch drum 90 is journalled upon the extension 84. It includes an internally splined periphery 92 to facilitate a splined connection with one or more clutch discs 94. A clutch back-up member 96 also is externally splined to the interior of drum. 9t and held axially fast by snap ring 98.

Drum 90 defines an annular cylinder 180 within which is positioned an annular piston 102. The piston and cylinder cooperate to define a pressure cavity that communicates with the pressure feed port 184.

A return spring in the form of stacked Belleville washer springs 106 acts upon the iston 102. Springs 186 are secured to the hub of drum 98 by means of a snap ring 108. The disc 94 directly adjacent the piston 102 is secured thereto by a plurality of screws 110. If desired, one or more dowel pins 112 can be employed also for this purpose.

Port 104 communicates with a port 114 formed in extension 84. This port in turn communicates with an annular recess 116 formed in wall 72. Recess 116 in turn communicates with a pressure feed passage 118. The ring 76 is formed with a threaded opening 128 which communicates with the passage 118. A suitable threaded fitting can be received within the threaded opening 126 to establish a fluid connection with a pressure feed passage.

A ball check valve 122 is located in the drum 90 at a radially outward location. It is adapted to be seated upon a conical valve seat disposed about an exhaust opening. When fluid pressure is admitted to the cavity 188, valve 122 assumes a closed position against this conical valve seat. As clutch pressure is exhausted from the cavity 180, however, centrifugal force urges the ball valve 122 away from its seat thereby establishing a direct connection between the interior of the cavity 180 and the exhaust region. The fluid within the cavity thus is exhausted into the exhaust region and a centrifugal clutch pressure build-up thus is avoided. The fluid is replaced by air that is admitted into the cavity 180 through an air bleed passage 124.

An externally splined clutch element 126 carries internally splined clutch disc's 128 which are situated in interdigital relationship with respect to discs 94. Clutch element 126 is keyed to sleeve shaft 48 as shown at 138.

Back-up member 96 is formed with an axially extending shaft extension 132 which is journalled within an opening 134 formed in a separating wall 136. This wall is secured at its periphery to a boss 138 formed in the interior of the housing portion 12. Wall 136 defines also a bearing opening 140 for a bearing 142 which journals clutch member 144. A sleeve 46 extends from member 144 and is keyed to extension 122 by means of a key 148 thereby establishing a direct connection between member 144 and the clutch drum 90. An end wall 150 is secured by means of bolts 152 to a peripheral boss 154 formed in the housing portion 12. Wall 150 is formed with a bearing opening 156 which receives a ball bearing 158. This bearing journals a fan drive shaft 160 having a radially extending drive plate 162. A clutch ring 164 is connected to the periphery of plate 162 by means of bolts 166 and dowels 168. Ring 164 is internally splined to permit a driving connection with externally splined clutch discs 170. Internally splined discs 172 are carried by a clutch member 174 which is connected to or formed integrally with the shaft 20. A clutch back-up disc 176 is secured to the drive member 162 adjacent one of the discs 172. A clutch pressure disc 178 has its peripheral portion disposed adjacent one of the discs and is pinned thereto as shown at 180.

Pressure disc 178 is formed with an annular recess 182 which defines an annular cylinder. An annular piston 184 is disposed within cylinder 182 and includes an extension 186 received within an opening formed in the hub of disc 178. This extension 186 engages one end of the member 144. A retainer nut 188 holds the piston 1.84 against movement in a left hand direction, as viewed in FlGURE 1.

A spring seat member 190 is secured at its periphery to the ring 164 by means of the bolts 166 and the dowel pins 168. Back-up member 190 is riveted or otherwise secured to the member 144. Clutch apply springs 192 are situated between spring seat member 190 and the pressure disc 178.

Member 190 is formed with cam portions 194 in the form of recesses which receive cam balls 196. These balls are disposed between pressure disc 178 and the cam surface defined by the cam portions 194.

During rotation of the clutch structure the centrifugal force that is developed due to the mass of the balls 198 will exert a clamping force upon the clamping disc 178 thereby maintaining a frictional driving connection between the discs 172 and 170. This supplements the action of the springs 192.

Piston 184 and the cylinder 182 define a pressure cavity that is in fluid communication with an annular recess 198 formed inthe member 144. This communication is established by ports 200 and port 202 formed in piston 184 and in member 144, respectively. A fluid pressure distributor sleeve 204 surrounds shaft 20 and cooperates with the recess 198 to define an axially extending flow passage. Member 144 is formed with a port 206 that communicates with the recess 198. This port in turn communicates with ports 2118 which form an extension of a feed passage 210 formed in the wall 136, Passage 218 in turn communicates with a passage 212 formed in the housing portion 12. Passage 212 is threaded at 214 to receive a fluid fitting that establishes a fluid connection with a pressure feed line. Thus as fluid pressure is admitted into the passage 212, the pressure disc 178 is urged to a clutch disc disengaging position against the opposing influence of the springs 192 and the opposed centrifugal force established by the balls 196.

Fan drive shaft 168 is splined at 216 to the hub 218 of the cooling fan. It is held in place by a retainer nut 220. A fluid seal 222 surrounds a hub extension 224 and is held in place by a seal retainer 226 which is secured by bolts 228 to the wall 150.

Cooling fan blades 2311 are secured to the periphery of the hub 218. A suitable key and slot connection or a splined connection can be provided for this purpose. Blades 230 are held axially fast by a retainer ring 232 secured to the hub 218 by bolts 234.

An annular shroud 236 surrounds the blades 230. It is formed with stationary webs in the form of blades 238. These are formed integrally with an inner annular shroud 240 which is bolted by means of bolts 152 to the boss 154.

During operation engine torque is delivered from shaft 220 to the ring gear 26. If the drive is conditioned for low speed ratio operation, ring gear "26 drives carrier 36 at a reduced speed as the sun gear 28 acts as a reaction member. This causes sleeve shaft 40 to drive clutch member 126. If the clutch structure shown in part at 92 and 94 is applied, driving torque then is delivered from shaft 41) through the rear clutch to the member 144. This causes shaft 160 to be driven at the same speed as the speed of rotation of the carrier 36. Thus the fan blades 230 are driven at a reduced speed relative to the speed of rotation of the shaft 20.

The rear clutch can be applied by introducing pressure into the passage 118. This pressurizes cavity 100 thereby establishing a driving connection between sleeve shaft 40 and the clutch drum 90.

To condition the drive for high speed ratio operation, the rear clutch shown in part at 92 and 94 is released and the front clutch shown in part at 170 and 172 is applied. This is done by exhausting fluid pressure from passage 212 thereby allowing the springs 192 to engage the discs 170 and 172. Engine torque then is delivered through shaft 20 and through the front clutch, shown in part at 170 and 172, to the shaft 160. The fan blades 230 then are driven at the same speed of rotation of the shaft 20.

The pump shown in part at 54 and 56 acts as a pressure source for applying the high range clutch and the low range clutch. The control system for distributing pressure from the pump to each of the clutches is illustrated in FIGURE 2. In FIGURE 2 an electrical conduit 242 is connected to the vehicle master ignition switch which may be energized by a 24 volt supply. This conduit is connected to conduit 244 through a water detector switch 246. Conduit 244 in turn is connected through a thermostatically controlled low temperature switch 248 to conduit 250 which extends to a neutral solenoid 252. The solenoid is grounded through a ground line 254. When the solenoid 252 is energized in this fashion, it moves a solenoid valve 256 in a left hand direction as viewed in FIGURE 2, thereby establishing a direct connection between passage 212 and pump discharge passage 68. At the same time a direct connection is established between fluid pressure passage 258 and the low pressure exhaust region which is indicated in FIGURE 2 by a transmission sump 260. Passage 258 has disposed therein a pressure reducer valve 262 which acts to reduce the effective pressure in passage 258 to a calibrated value.

The output pressure of the reducer valve is distributed through a passage 264 to an interlock valve 266. This valve is actuated by means of a hydraulic servo 268 to either one of two positions. Servo 268 responds to pressure in passage 212 to urge the interlock valve 266 to the position shown in FIGURE 2. When it assumes this position pressure distribution from passage 264 to the low range clutch feed passage 68 is established. At the same time passage 68 is disconnected from the exhaust region, which again is indicated as a sump 260.

The interlock valve prevents simultaneous application of the high range clutch and the low range clutch. When pressure in the passage 212 is exhausted, a spring returns the interlock valve to a left hand position thereby blocking communication between passage 264 and passage 68. At the same time communication between passage 68 and the exhaust region is established.

When the solenoid valve 256 assumes the position shown in FIGURE 2, both the high range clutch and the low range clutch become exhausted so that the two speed drive automatically will assume a high speed range. If the engine coolant temperature reaches approximately 180 F., the low temperature switch 248 will be opened by the action of a suitable thermostat thereby de-energizing the electrical solenoid 252. At the same time the switch 248 makes contact with a conduit 270 which forms a part of the circuit for a low solenoid 272. This solenoid is grounded at 274. The low solenoid 272 thus becomes energized and the solenoid valve 256 movefio the right to the low speed range position. This allows pressure from the pump to pass through passage 68 and directly to passage 212 thus releasing the high range clutch.

6 Pressure is distributed also to the passage 258 and hence to the low range clutch, thereby applying the latter.

The pressure of the pump shown at 54 and 56- is regulated by an appropriate regulator valve 276.

During operation of the fan drive in the low speed range, the speed of the fan is reduced by a factor of 1.59. If the engine speed is 2200 rpm, the maximum horsepower required by the fan in a typical installation is 31 horsepower. In contrast, the maximum power of about horsepower is required if the fan is driven in the high speed range with the same engine speed.

If the coolant temperature increases to a value in excess of 227 F., a thermostatically controlled high temperature switch, shown at 278, becomes open thereby deenergizing the low range solenoid 272. The solenoid valve 256, which is spring centered, then shifts to the high range position shown in FIGURE 2. This interrupts the supply of clutch pressure to both the high range clutch and the low range clutch.

If there is a failure in the electric or hydraulic circuits, the fan drive automatically will assume the high range position by reason of the centering action of the springs for the solenoid valve 256.

If the vehicle enters water and the water level reaches the fan compartment, the water detector switch 246 is actuated. This interrupts the connection with conduit 244 and establishes a direct connection with conduit 250 which causes the neutral solenoid to become energized thereby shifting the transmission to neutral. The fan drive will remain in neutral until the vehicle is back on land and the water drains out of the fan compartment. The control system then will respond in the mannner previously described so that the operating range will be dependent upon the coolant temperature.

If the ambient air temperature decreases or the cooling requirements diminish, the coolant temperature will decrease. When the coolant temperature decreases to 220 F., the high temperature switch will become actuated thereby energizing the low range solenoid and shifting the transmission into the low range. The fan drive then will operate in the low range until the coolant temperature decreases to approximately F., at which time it is caused to shift to neutral by reason of the operation of the low temperature switch. A fan is not required for cooling purposes when the temperature is below 180 F.

In FIGURE 3 we have illustrated in graphic form the fan horsepower as the engine speed varies during operation. This curve has been plotted for a typical driveline installation wherein the high speed drive ratio is 2.31 times engine speed and the low speed drive ratio is 1.59 times engine speed.

It can be observed readily from an inspection of FIG- URE 3 that the horsepower savings can be substantial if the drive is shifted .to the low speed range in those instances when the cooling requirements of the engine are less than the maximum.

A clutch plate separator wire 280 is disposed directly adjacent the center clutch plate 170 and is held axially fast by a cooperating groove in the internal spline teeth of ring 164. Thus when the drive is tilted from the horizontal position, the weight of this disc 170 will not cause it to drag against the adjacent disc 172. Undue wear of the disc and a reduction in mechanical efiiciency are thus avoided when the drive operates about a generally vertical axis.

Having thus described a preferred form of our invention, what we claim and desire to secure by US. Letters Patent is:

4 1. In a multiple speed drive mechanism for an engine cooling fan, a power input shaft, a power output shaft adapted to be connected to a bladed fan, a planetary gear unit comprising a sun gear element, a carrier element, a ring gear element and planet pinions rotatably mounted on said carrier element in meshing engagement with said sun gear element and said ring gear element, said power input shaft being connected to one element of said planetary gear unit, a second element of said planetary gear unit being connected to relatively stationary portions of said mechanism, a direct drive clutch structure comprising a rotary drum connected to said power output shaft, means including a selectively engageable low speed clutch for drivably connecting a third element of said planetary gear unit to said drum, spring means carried by said drum for engaging said direct drive clutch structure, fluid pressure operated servo means disposed within said drum for overruling the action of said spring means in response to a pressure build-up therein whereby said direct drive clutch is released.

2. A fan drive mechanism for delivering power from a vehicle engine to an engine cooling fan comprising a power input shaft, a power output shaft, a planetary gear unit comprising a ring gear, a sun gear, a carrier, planet pinions rotatably supported on said carrier in meshing engagement with said sun gear and said ring gear, a relatively stationary drive housing, said sun gear being connected to said housing and adapted thereby to function as a torque reaction member, means for connecting said power input shaft to said ring gear, a low-speed clutch drum rotatably mounted about the axis of said power input shaft, selectively engagable friction clutch means defined in part by said low speed clutch drum for connecting said power output shaft to said carrier, said drum defining an annular cylinder, an annular piston enclosed in said annular cylinder, servo means defined in part by said cylinder and said piston for engaging selectively said clutch means in response to a pressure build-up in said cylinder, a high-speed ratio clutch comprising a high speed clutch drum connected to said power output shaft, high speed clutch means defined in part by said high speed clutch drum for connecting drivably said power input shaft to said power output shaft, and including first friction clutch elements connected to said high speed clutch drum, second friction clutch elements connected to said power input shaft, said first and second friction elements being disposed in adjacent relationship, spring means for applying an engaging force to said friction elements to establish a direct connection between said power input shaft and said power output shaft, and fluid pressure operated servo means disposed within said high speed clutch drum for moving said spring means thereby releasing the driving connection between said power input shaft and said power output shaft.

3. In a multiple speed drive mechanism for an engine cooling fan, a power input shaft, a power output shaft adapted to be connected to a bladed fan, a planetary gear unit comprising a sun gear element, a carrier element, a ring gear element and planet pinions rotatably mounted on said carrier element in meshing engagement with said sun gear element and said ring gear element, said power input shaft being connected to one element of said planetary gear unit, a second element of said planetary gear unit being connected to relatively stationary portions of said mechanism, a direct drive clutch structure comprising a rotary drum connected to said driven shaft and cooperating friction elements connected to said drum and said power input shaft, means including a selectively engagable low speed clutch for drivably connecting a third element of said planetary gear unit to said drum, fluid pressure operated servo means for applying said low speed clutch in response to a pressure build-up therein, spring means carried by said drum for engaging said direct drive clutch structure, fluid pressure operated servo means disposed within said drum for overruling the action of said spring means in response to a pressure build-up therein whereby said direct drive clutch is released, said direct drive clutch structure including a pressure plate adjacent said friction elements, said spring means engaging said pressure plate whereby clutch engaging forces are applied to said friction elements, said pressure plate defining an annular cavity, and a wall disposed in said cavity and cooperating therewith to define a pressure chamber, said pressure plate being urged out of frictional engagement with said friction elements upon introduction of fluid pressure into said chamber.

4. A fan drive mechanism for delivering power from a vehicle engine to an engine cooling fan comprising a power input shaft, a power output shaft, a planetary gear unit comprising a ring gear, a sun gear, a carrier, planet pinions rotatably supported on said carrier in meshing engagement with said sun gear and said ring gear, a relatively stationary drive housing, said sun gear being connected to said housing and adapted thereby to function as a torque reaction member, means for connecting said power input shaft to said ring gear, a low-speed clutch drum rotatably mounted about the axis of said power input shaft, selectively engagable low speed friction clutch means defined in part by said low speed clutch drum for connecting said power output shaft to said carrier, said drum defining an annular cylinder, an annular piston enclosed in said annular cylinder, servo means defined in part by said cylinder and said piston for engaging selectively said clutch means in response to a pressure build-up in said cylinder, at high-speed clutch comprising a high speed clutch drum connected to said power output shaft, high speed clutch means defined in part by said high speed clutch drum for connecting drivably said power input shaft to said power output shaft, and including first friction clutch elements connected to said high speed clutch drum, second friction clutch elements connected to said power input shaft, said first and second friction elements being disposed in adjacent relationship, spring means for applying an engaging force to said friction elements to establish a direct connection between said power input shaft and said power output shaft, fluid pressure operated servo means disposed within said high speed clutch drum for moving said spring means thereby releasing the driving connection between said power input shaft and said power output shaft, said high speed clutch means comprising a pressure plate adjacent said clutch elements, said spring means engaging said pressure plate whereby clutch engaging forces are applied to said clutch elements, said pressure plate defining an annular cavity, a Wall disposed in said cavity and cooperating therewith to define a pressure chamber, said pressure plate being urged out of frictional engagement with said clutch elements upon introduction of fluid pressure into said chamber.

5. In a multiple speed drive mechanism for an engine cooling fan, a power input shaft, apower output shaft adapted to be connected to a bladed fan, a planetary gear unit comprising a sun gear element, a carrier element, a ring gear element and planet pinions rotatably mounted on said carrier element in meshing engagement with said sun gear element and said ring gear element, said power input shaft being connected to one element of said planetary gear unit, a second element of said planetary gear unit being connected to relatively stationary portions of said mechanism, a direct drive clutch comprising a rotary drum connected to said power output shaft, means including a selectively engageable low speed clutch for drivably connecting a third element of said planetary gear unit to said drum, spring means carried by said drum for engaging said direct drive clutch structure, fluid pressure operated servo means disposed within said drum for overruling the action of said spring means in response to a pressure build-up therein whereby said direct drive clutch is released, a fluid pressure source, conduit structure interconnecting said pressure source with each clutch means, drive range selector valve means disposed in and partly defining said conduit structure for controlling the operation of each clutch means including a movable valve element adapted to assume any one of three positions, said valve element accommodating distribution of pressure to each clutch means as it assumes one position, each clutch means being exhausted and pressure distribution to each clutch means being interrupted when said Valve 9 element assumes a second position, said valve element being adapted to distribute pressure to said high speed clutch means while exhausting said low speed clutch means as said valve element assumed a third position, and spring means for normally biasing said valve element to said second position.

6. A fan drive mechanism for delivering power from a vehicle engine to an engine cooling fan comprising a power input shaft, a power output shaft, a planetary gear unit comprising a ring gear, a sun gear, a carrier, planet pinions rotatably supported on said carrier in meshing engagement with said sun gear and said ring gear, a relatively stationary drive housing, said sun gear being connected to said housing and adapted thereby to function.

as a torque reaction member, means for connecting said power input shaft to said ring gear, a low-speed clutch drum rotatably mounted about the axis of said power input shaft selectively engageable low speed friction clutch means defined in part by said low speed clutch drum for con-necting said power output shaft to said carrier, said drum defining an annular cylinder, an annular piston enclosed in said annular cylinder, servo means defined in part by said cylinder and said piston for engaging selectively said low speed clutch means in response to a pressure build-up in said cylinder, a high-speed clutch comprising a high speed clutch drum connected to said power output shaft, high speed clutch means defined in part by said high speed clutch drum for connecting drivably said power input shaft to said power output shaft, and including first friction clutch elements connected to said high speed clutch drum, second friction clutch elements connected to said power input shaft, said first and second friction elements being disposed in adjacent relationship, spring means for applying an engaging force to said friction elements to establish a direct connection between said power input shaft and said power output shaft, fluid pressure operated servo means disposed within said high speed clutch drum for moving said spring means thereby releasing the driving connection between said power input shaft and said power output shaft, a fluid pressure source, conduit structure interconnecting said pressure source with each clutch means, drive range selector valve means disposed in and partly defining said conduit structure for controlling the operation of said clutch means including a movable valve element adapted to assume any one of three positions, said valve element accommodating distribution of pres sure to each clutch means as it assumes one position, each clutch means being exhausted and pressure distribution to each clutch means being interrupted when said valve element assumes a second position, said valve element being adapted to distribute pressure to said high speed clutch means while exhausting said low speed clutch means as said valve element assumes a third position, and spring means for normally biasing said valve element to said second position.

7. In a multiple speed drive mechanism for an engine cooling fan, a power input shaft, a power output shaft adapted to be connected to a bladed fan, a planetary gear unit comprising a sun gear element, a carrier element, a ring gear element and planet pinions rotatably mounted on said carrier element in meshing engagement with said sun gear element and said ring gear element, said power input shaft being connected to one element of said planetary gear unit, a second element of said planetary gear unit being connected to relatively stationary portions of said mechanism, a direct drive clutch comprising a rotary drum connected to said power output shaft, means including a selectively engageable low speed clutch for drivably connecting a third element of said planetary gear unit to said drum, spring means carried by said drum for engaging said direct drive clutch structure, fluid pressure operated servo means disposed within said drum for overruling the action of said spring means in response to a pressure build-up therein whereby said direct drive clutch is released, said direct drive clutch structure including a pressure plate adjacent the friction portion of said direct drive clutch, said spring means engaging said pressure plate whereby clutch engaging forces are applied to said friction portion, said pressure plate defining an annular cavity, a wall disposed in said cavity and cooperating therewith to define a pressure chamber, said pressure plate being urged out of frictional engagement with said friction portion upon introduction of fluid pressure into said chamber, a fluid pressure source, conduit structure interconnecting said pressure source with each clutch servo means, drive range selector valve means disposed in and partly defining said conduit structure for controlling the operation of said clutch means including a movable valve element adapted to assume any one of three positions, said valve element accommodating distribution of pressure to each clutch means as it assumes one position, each clutch means being exhausted and pressure distribution to each clutch means being interrupted when said valve element assumes a second position, said valve element being adapted to distribute pressure to said high speed clutch means while exhausting said low speed clutch means as said valve element assumes a third position, and spring means for normally biasing said valve element to said second position.

8. A fan drive mechanism for delivering power from a vehicle engine to an engine cooling fan comprising a power input shaft, a power output shaft, a planetary gear unit comprising a ring gear, a sun gear, a carrier, planet pinions rotatably supported on said carrier in meshing engagement with said sun gear and said ring gear, a relatively stationary drive housing, said sun gear being connected to said housing and adapted thereby to function as a torque reaction member, means for connecting said power input shaft to said ring gear, a low-speed clutch drum rotatably mounted about the axis of said power input shaft, selectively engageable low speed friction clutch means defined in part by said low speed clutch drum for connecting said power output shaft to said carrier, said drum defining an annular cylinder, an annular piston enclosed in said annular cylinder, servo means defined in part by said cylinder and said piston for engaging selectively said low speed clutch means in response to a pressure build-up in said cylinder, a high-speed clutch comprising a high speed clutch drum connected to said power output shaft, high speed clutch means defined in part by said high speed clutch drum for connecting drivably said power input shaft to said power output shaft, and including first friction clutch elements connected to said high speed clutch drum, second friction clutch elements connected to said power input shaft, said first and second friction elements being disposed in adjacent relationship, spring means for applying an engaging force to said fric tion elements to establish .a direct connection between said power input shaft and said power output shaft, fluid pressure operated servo means disposed within said high speed clutch drum for moving said spring means thereby releasing the driving connection between said power input shaft and said power output shaft, said high speed clutch means comprising a pressure plate adjacent said clutch elements, said spring means engaging said pressure plate whereby clutch engaging forces are applied to said clutch elements, said pressure plate defining .an annular cavity, a wall disposed in said cavity and cooperating therewith to define a pressure chamber, said pressure plate being urged out of frictional engagement with said clutch elements upon introduction of fluid pressure into said chamber, a fluid pressure source, conduit structure interconnecting said pressure source with each clutch means, drive range selector valve means disposed in and partly defining said conduit structure for controlling the operation of said clutch means including a movable valve element adapted to assume any one of three positions, said valve element accommodating distribution of pressure to each clutch means as it assumes one position, each clutch means being exhausted and pressure distribution to each clutch means being interrupted when said valve element assumes a second position, said valve element being adapted to distribute pressure to said high speed clutch means while exhausting said low speed clutch means as said valve element assumes a third position, and spring means for normally biasing said valve element to said second position.

9. In a multiple speed drive mechanism for an engine cooling fan, a power input shaft, a power output shaft adapted to be connected to a bladed fan, a planetary gear unit comprising a sun gear element, a carrier element, a ring gear element and planet pinions rotatably mounted on said carrier element in meshing engagement with said sun gear element and said ring gear element, said power input shaft being connected to one element of said planetary gear unit, a second element of said planetary gear unit being connected to relatively stationary portions of said mechanism, a direct drive clutch comprising a rotary drum connected to said power output shaft, means including a selectively engageable low speed clutch for drivably connecting a third element of said planetary gear unit to said drum, spring means carried by said drum for engaging said direct drive clutch structure, fluid pressure operated servo means disposed within said drum for overruling the action of said spring means in response to a pressure build-up therein whereby said direct drive clutch is released, a fluid pressure source, conduit structure interconnecting said pressure source with each clutch means, drive range selector valve means disposed in and partly defining said conduit structure for controlling the operation of each clutch means including a movable valve element adapted to assume any one of three positions, said valve element accommodating distribution of pressure to each clutch means as it assumes one position, each clutch means being exhausted and pressure distribution to each clutch means being interrupted when said valve element assumes a second position, said valve element being adapted to distribute pressure to said high speed clutch means while exhausting said low speed clutch means as said valve element assumes a third position, spring means for normally biasing said valve element to said second position, first control means in the form of a neutral solenoid for urging said valve element from the second position to the third position as it is energized, second control means in the form of a low speed solenoid for urging said valve element from the second position to the first position as it is energized, a source of electrical energy and a switching circuit for connecting said electrical source to each of said solenoids including separate portions extending to each solenoid, a thermostatically controlled low temperature switch means for connecting said source to said neutral solenoid circuit when the operating temperature is low and to said low solenoid circuit when the operating temperature is greater than an intermediate value, and a high temperature switch means form ing a part of the low speed solenoid circuit portion for actuating the low speed solenoid when the operating temperature is greater than an upper limit.

10. A fan drive mechanism for delivering power from a vehicle engine to an engine cooling fan comprising a power input shaft, a power output shaft, a planetary gear unit comprising a ring gear, a sun gear, a carrier, planet pinions rotatably supported on said carrier in meshing engagement with said sun gear and said ring gear, a relatively stationary drive housing, said sun gear being connected to said housing and adapted thereby to function as a torque reaction member, means for connecting said power input shaft to said ring gear, a low-speed clutch drum rotatably mounted about the axis of said power input shaft, selectively engageable low speed friction clutch means defined in part by said low speed clutch drum for connecting said power output shaft to said carrier, said drum defining an annular cylinder, an annular piston enclosed in said annular cylinder, servo means defined in part by said cylinder and said piston for engaging selectively said low speed clutch means in response to a pressure build-up in said cylinder, a high-speed clutch comprising a high speed clutch drum connected to said power output shaft, high speed clutch means defined in part by said high speed clutch drum for connecting drivably said power input shaft to said power output shaft, and including first friction clutch elements connected tosaid high speed clutch drum, second friction clutch elements connected to said power input shaft, said first and second friction elements being disposed in adjacent relationship, spring means for applying an engaging force to said friction elements to establish a direct connection between said power input shaft and said power output shaft, fluid pressure operated servo means disposed within said high speed clutch drum for moving said spring means thereby releasing the driving connection between said power input shaft and said power output shaft, said high speed clutch means comprising a pressure plate adjacent said clutch elements, said spring means engaging said pressure plate whereby clutch engaging forces are applied to said clutch elements, said pressure plate defining an annular cavity, a wall disposed in said cavity and cooperating therewith to define a pressure chamber, said pressure plate being urged out of frictional engagement with said clutch elements upon introduction of fluid pressure into said chamber, a fluid pressure source, conduit structure interconnecting said pressure source with each clutch means, drive range selector valve means disposed in and partly defining said conduit structure for controlling the operation of said clutch means including a movable valve element adapted to assume any one of three positions, said valve element accommodating distribution of pressure to each clutch means as it assumes one position, each clutch means being exhausted and pressure distribution to each clutch means being interrupted when said valve element assumes a second position, said valve element being adapted to distribute pressure to said high speed clutch means while exhausting said low speed clutch means as said valve element assumes a third position, spring means for normally biasing said valve element to said second position, first control means in the form of a neutral solenoid for urging said valve element from the second position to the third position as it is energized, second control means in the form of a low speed solenoid for urging said valve element from the second position to the first position as it is energized, a source of electrical energy and a switching circuit for connecting said electrical source to each of said solenoids including separate portions extending to each solenoid, a thermostatically controlled low temperature switch means for connecting said source to said neutral solenoid circuit when the operating temperature is low and to said 10w solenoid circuit when the operating temperature is greater than an intermediate value, and a high temperature switch means forming a part of the low speed solenoid circuit portion for actuating said low speed solenoid when the operating temperature is greater than an upper limit.

11. In a multiple speed drive mechanism for an engine cooling fan, a power input shaft, a power output shaft adapted to be connected to a bladed fan, a planetary gear unit comprising a sun gear element, a carrier element, a ring gear element and planet pinions rotatably mounted on said carrier element in meshing engagement with said sun gear element and said ring gear element, said power input shaft being connected to one element of said planetary gear unit, a second element of said planetary gear unit being connected to relatively stationary portions of said mechanism, a direct drive clutch comprising a rotary drum connected to said power output shaft, means including a selectively engageable low speed clutch for drivably connecting a third element of said planetary gear unit to said drum, spring means carried by said drum for engaging said direct drive clutch structure, fluid pressure operated servo means disposed within said drum for overruling the action of said spring means in response to a pressure build-up therein whereby said direct drive clutch is released, a fluid pressure source, conduit structure interconnecting said pressure source with each clutch means, drive range selector valve means disposed in and partly defining said conduit structure for controlling the operation of each clutch means including a movable valve element adapted to assume any one of three positions, said valve element accommodating distribution of pressure to each clutch means as it assumes one position, each clutch means being exhausted and pressure distribution to each clutch means being interrupted when said valve element assumes a second position, said valve element being adapted to distribute pressure tosaid high speed clutch means while exhausting said low speed clutch means as said valve element assumes a third position, spring means for normally biasing said valve element to said second position, said high speed clutch means comprising a clutch pressure plate, said first mentioned spring means engaging said pressure plate to establish clutch engaging forces, said pressure plate defining an annular cavity, a Wall disposed in said cavity and cooperating therewith to define a pressure chamber, said pressure plate being urged toward a released position upon introduction of fluid pressure to said chamber, first control means in the form of a neutral solenoid for urging said valve element from the second position to the third position as it is energized, second control means in the form of a low speed solenoid for urging said valve element from the second position to the first position as it is energized, a source of electrical energy and a switching circuit for connecting said electrical source to each of said solenoids including separate portions extending to each solenoid, a thermostatically controlled low temperature switch means for connecting said source to said neutral solenoid circuit when the operating temperature is low and to said low solenoid circuit when the operating temperature is greater than an intermediate value, and a high temperature switch means forming a part of the low speed solenoid circuit portion for actuating the low speed solenoid when the operating temperature is greater than an upper limit.

12. A fan drive mechanism for delivering power from a vehicle engine to an engine cooling fan comprising a power input shaft, a power output shaft, a planetary gear unit comprising a ring gear, a sun gear, a carrier, planet pinions rotatably supported on said carrier in meshing engagement with said sun gear and said ring gear, a relatively stationary drive housing, said sun gear being connected to said housing and adapted thereby to function as a torque reaction member, means for connecting said power input shaft to said ring gear, a low-speed clutch drum rotatably mounted about the axis of said power input shaft, selectively engageable low speed friction clutch means defined in part by said low speed clutch drum for connecting said power output shaft to said carrier, said drum defining an annular cylinder, an annular piston enclosed in said annular cylinder, servo means defined in part by said cylinder and said piston for engaging selectively said low speed clutch means in response to a pressure build-up in said cylinder, a high-speed clutch comprising a high speed clutch drum connected to said power output shaft, high speed clutch means defined in part by said high speed clutch drum for connecting drivably said power input shaft to said power output shaft, and including first friction clutch elements connected .to said high speed clutch drum, sec-nd friction clutch elements connected to said power input shaft, said first and second friction elements being disposed in adjacent relationship, spring means for applying an engaging force to said friction elements to establish a direct connection between said power input shaft and said power output shaft, fluid pressure operated servo means disposed within said high speed clutch drum for moving said spring means thereby releasing the driving connection between said power input shaft and said power output shaft, said high speed clutch means comprising a pressure plate adjacent said clutch elements, said spring means engaging said pressure plate whereby clutch engaging forces are applied to said clutch elements, said pressure plate defining an annular cavity, a wall disposed in said cavity and cooperating therewith to define a pressure chamber, said pressure plate being urged out of frictional engagement with said clutch elements upon introduction of fluid pressure into said chamber, a fluid pressure source, conduit structure interconnecting said pressure source with each clutch means, drive range selector valve means disposed in and partly defining said conduit structure for controlling the operation of said clutch means including a movable valve element adapted to assume any one of three positions, said valve element accommodating distribution of pressure to each clutch means as it assumes one position, each clutch means being exhausted and pressure distribution to each clutch means being interrupted when said valve element assumes a second position, said valve element being adapted to distribute pressure to said high speed clutch means while exhausting said low speed clutch means as said valve element assumes a third position, spring means for normally biasing said valve element to said second position, first control means in the form of a neutral solenoid for urging said valve element from the second position to the third position as it is energized, second control means in the form of a low speed solenoid for urging said valve element from the second position to the first position as it is energized, a source of electrical energy and a switching circuit for connecting said electrical source to each of said solenoids including separate portions extending to each solenoid, a thermostatically controlled low tem perature switch means for connecting said source to said neutral solenoid circuit when the operating temperature is low and to said low solenoid circuit when the operating temperature is greater than an intermediate value, and a high temperature switch means forming a part of the low speed solenoid circuit portion for actuating said low speed solenoid when the operating temperature is greater than an upper limit, and a water detector switch means adapted to interrupt the connection between said electrical source and said low speed solenoid and establish a direct connection between said source and said neutral solenoid when it is actuated.

13. In a multiple speed drive mechanism for an engine cooling fan, :a power input shaft, a power output shaft adapted to be connected to a bladed fan, a planetary gear unit comprising a sun gear element, a carrier element, a ring gear element and planet pinions rotatably mounted on said carrier element in meshing engagement with said sun gear element and said ring gear element, said power input shaft being connected to one element of said planetary gear unit, a second element of said planetary gear unit being connected to relatively stationary portions of said mechanism, a direct drive clutch comprising a rotary drum connected to said power output shaft, means including a selectively engageable low speed clutch for drivably connecting a third element of said planetary gear unit to said drum, spring means carried by said drum for engaging said direct drive clutch structure, fluid pressure operated servo means disposed within said drum for overruling the action of said spring means in response to a pressure build-up therein whereby said direct drive clutch is released, a fluid pressure source, conduit structure interconnecting each clutch means and said source, an interlock valve means disposed in and partly defining said conduit structure for interrupting distribution of said pressure to said low speed clutch means when pressure distribution to said high speed clutch means is interrupted and for distributing pressure to said low speed clutch means when pressure is introduced to said high speed clutch means.

14. A fan drive mechanism for delivering power from a vehicle engine to an engine cooling fan comprising a power input shaft, a power output shaft, a planetary gear unit comprising a ring gear, a sun gear, a carrier, planet pinions rotatably supported on said carrier in meshing engagement with said sun gear and said ring gear, a relatively stationary drive housing, said sun gear being connected to said housing and adapted thereby to function as a torque reaction member, means for connecting said power input shaft to said ring gear, a lowspeed clutch drum rotatably mounted about the axis of said power input shaft, selectively engageable friction clutch means defined in part by said low speed clutch drum for connecting said power output shaft to said carrier, said drum defining an annular cylinder, an annular piston enclosed in said annular cylinder, servo means defined in part by said cylinder and said piston for engaging selectively said clutch means in response to a pressure build-up in said cylinder, a high-speed ratio clutch comprising a high speed clutch drum connected to said power output shaft, high speed clutch means defined in part by said high speed clutch drum for connecting drivably said power input shaft to said power output shaft, and including first friction clutch elements connected to said high speed clutch drum, second friction clutch elements connected to said power input shaft, said first and second friction elements being disposed in adjacent relationship, spring means for applying an engaging force to said friction elements to establish a direct connection between said power input shaft and said power output shaft, fluid pressure operated servo means disposed within said high speed clutch drum for moving said spring means thereby releasing the driving connection between said power input shaft and said power output shaft, a fluid pressure source, conduit structure interconnecting each clutch means and said source, an interlock Valve means disposed in and partly defining said conduit structure for interrupting distribution of said pressure to said low speed clutch means when pressure distribution to said high speed clutch means is interrupted and for distributing pressure to said low speed clutch means when pressure is introduced to said high speed clutch means.

References fiited by the Examiner UNITED STATES PATENTS 2,194,823 3/1940 Dooley 74-781 2,386,220 10/1945 Lawler et a1. 74781 2,775,330 12/1956 Schjolin et a1 74750 FOREIGN PATENTS 869,456 11/1941 France.

DAVID J. WILLIAMOWSKY, Primary Examiner. T. C. PERRY, Assistant Examiner. 

1. IN A MULTIPLE SPEED DRIVE MECHANISM FOR AN ENGINE COOLING FAN, A POWER INPUT SHAFT, A POWER OUTPUT SHAFT ADAPTED TO BE CONNECTED TO A BLADED FAN, A PLANETARY GEAR UNIT COMPRISING A SUN GEAR ELEMENT, A CARRIER ELEMENT, A RING GEAR ELEMENT AND PLANET PINIONS ROTATABLY MOUNTED ON SAID CARRIER ELEMENT IN MESHING ENGAGEMENT WITH SAID SUN GEAR ELEMENT AND SAID RING GEAR ELEMENT, SAID POWER INPUT SHAFT BEING CONNECTED TO ONE ELEMENT OF SAID PLANETARY GEAR UNIT, A SECOND ELEMENT OF SAID PLANETARY GEAR UNIT BEING CONNECTED TO RELATIVELY STATIONARY PORTIONS OF SAID MECHANISM, A DIRECT DRIVE CLUTCH STRUCTURE COMPRISING A ROTARY DRUM CONNECTED TO SAID POWER OUTPUT SHAFT, MEANS INCLUDING A SELECTIVELY ENGAGEABLE LOW SPEED CLUTCH 